Spark plug



M. EYQUEM Sept. 23, 1930.

SPARK PLUG Filed Feb. 3, 1928 l j y@ e Q 7//////// \\i Patented Sept. 23, 1930 UNITED STATES PATENT oFFlcE nmol Houmt, or raars, runen arm raue Application iled February 3, 19.8, Serial lo. 3515, and in Belgium February 8, 1927.

The present inventionfrelates to sparku Ogle of the objects of the vinvention is to provide an improved form of seal which will prevent any possibility of leakage.

Another object is to improve the insulating material and the manner of applying the same so that the various conductors are properly insulated throughout the range of ordinary operating temperatures.

Still further objects will appear in the v course of the detailed description which will now be given with reference to the accompanying drawings, in which:-

Fig. 1 is a longitudinal section through one constructive embodiment of the invention;

Fig. 2 illustrates, in section, another modiication of the invention;

Fig. 3 shows still another form of plug constructed in accordance with the invention. A

Referring to the drawings, there is shown a central cylindrical conductor b terminating atone extremity in an enlarged rtion b1 and an electrode e and at its ot er extremity in a threaded'portion engaging with terminal block c adaptedrto be supplied with current from cable terminal lr-a series of insulating mica sheets f maintained in place on b by a sheath of paper or other flexible material f1 glued or otherwise aYdhesively attached to the longitudinal free edge of sheets f:-an outer casing a having a threaded portion a1 adapted to engage in the cylinder head a copper washer o seated on a shoulder a2 formed inside of casing az-a stack of mica washers g in the form of a truncated cone resting on b1 and slightly spaced from sheath f1 and washer 0:-a cylindrical sleeve L in threaded ment with easing a and adapted to hold washers g and o firmly in pomtionz-a pair of annular washers y' and i of tra idal section sliding over f1 with slight p ay and containing between them a'layer of finely pulverized insulatin material l: formed of staat-ite, quartz or the z-a ressure member l in threaded engagement with h and adapted .to act on washers j and i so esto force powder 1c centripetally against fl'and thus effectively seal the device and a stack of mica washers p inte osed between Z and c.

The mo 'lication shown in Fig. 2 diil'ers from that illustrated in Fig. 1 mainly in the form of the washers used for compressing powder k. Here washer of Fig. 1 is replaced by a member m resting directly on an internal shoulder of casing a and having its upper extremities turned over in contact N with washer j. Pressure member l of Fi 1 is eliminated, the turned over edges o m functioning to ress washer j down onto powder lc. The evice differs otherwise only in the positioning ofcopper washer o which is here interposed between a shoulder on member m and the end of sleeve h.

The device shown in Fig. 3 differs again only in details from that represented in Fig.

1. In this modilication mica washers g and 'N p Figs. 1 and 2 are replaced by porcelain, pyrex, or quartz elements p1 and f2, the latter having a central bore adapted to lit very closely over the uninsulated portion of ntral conductor b and with slight play over n insulated portion f. f2 is held firmly in place against copper washer el by sleeve h and serves as direct support for powder k. Only one wedge shaped washer j is used in this form of assembly, pressure being applied thereto by the overturned edge of sleeve h.

From the foregoing, it will be seen that in each modification means vare provided for forcing an insulating powder by a sort of wedging action into iirm-contact with the u only jointwhich is liable to leakage. It is to be understood that the invention is not to be taken as limited to the particular structures described. Thus, the mica insulating sheets enclosing conductor b may be replaced by a sheath of varnish, enamel, or an insulating resin formed of a phenol condensation product; the mechanical details shown in Fig. 1 such as pressure member l may be 95 transposed to the devices shown in Figs. 2 A and 3; an assembly involving the use of member m, Fig. 2, may be used in connection with the structures shown in Figs. 1 and 3; etc.

2. Y .Y mman- 1. In'a spark-plug, a sealing assembly includingv a conductor, a sheet of mica enclosing said conductor, and a flexible material continuously covering the free longitudinal edge of said mica sheet.

2. In a sparklug, a sealing assembly including a conductor, a sheet of mica partially enclosing said conductor adapted to insulate the latter, and la pulverized insulating material packed against said mica sheet.

3. In aspark-plug, a sea-ling assembly including a conductor, a sheet of mica partially enclosing said conductor, a. flexible material continuously covering the free longitudinal A edge of the mica sheet, and a pulverized insulating material packed around said Hexible material.

4. A spark-plug as defined in claim 2 in combination with means for forcing the 'pulverized .insulating material centripetally against the mica sheet.

5. A spark-plug as defined in claim 3 in g5 combination with means for forcing the pulverized insulating material centripetally against the mica sheet.

In testimony whereof I have -hereunto set my hand.

so MAURICE EYQUEM.

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